✅ QD-12615 Add tests for .mailmap support in contributors count

# Conflicts:
#	core/contributors_mailmap_test.go

Author: Shmulik Klein

core/contributors_mailmap_test.go

@@ -0,0 +1,132 @@
+/*
+ * Copyright 2021-2024 JetBrains s.r.o.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package core
+
+import (
+	"os"
+	"os/exec"
+	"path/filepath"
+	"testing"
+)
+
+func TestGetContributorsWithMailmap(t *testing.T) {
+	repo := newTestRepo(t)
+
+	repo.commit(t, "John Doe", "[email protected]")
+	repo.commit(t, "John Doe", "[email protected]")
+	repo.commit(t, "J. Doe", "[email protected]")
+	repo.commit(t, "Jane Smith", "[email protected]")
+
+	if got := len(GetContributors([]string{repo.dir}, -1, false)); got != 4 {
+		t.Errorf("Without mailmap: expected 4 contributors, got %d", got)
+	}
+
+	repo.writeMailmap(
+		t, `John Doe <[email protected]> <[email protected]>
+John Doe <[email protected]> <[email protected]>
+John Doe <[email protected]> J. Doe <[email protected]>
+`,
+	)
+
+	contributors := GetContributors([]string{repo.dir}, -1, false)
+	if got := len(contributors); got != 2 {
+		t.Errorf("With mailmap: expected 2 contributors, got %d", got)
+	}
+
+	johnCommits := countCommitsForEmail(contributors, "[email protected]")
+	if johnCommits != 3 {
+		t.Errorf("Expected John Doe to have 3 commits, got %d", johnCommits)
+	}
+}
+
+func TestGetContributorsMailmapNameMapping(t *testing.T) {
+	repo := newTestRepo(t)
+
+	repo.commit(t, "bobby", "[email protected]")
+	repo.commit(t, "Bob", "[email protected]")
+	repo.writeMailmap(t, "Robert Smith <[email protected]>\n")
+
+	contributors := GetContributors([]string{repo.dir}, -1, false)
+
+	if contributors[0].Author.Username != "Robert Smith" {
+		t.Errorf("Expected canonical name 'Robert Smith', got '%s'", contributors[0].Author.Username)
+	}
+	if contributors[0].Count != 2 {
+		t.Errorf("Expected 2 commits, got %d", contributors[0].Count)
+	}
+}
+
+type testRepo struct {
+	dir     string
+	counter int
+}
+
+func newTestRepo(t *testing.T) *testRepo {
+	dir := t.TempDir()
+	runGit(t, dir, nil, "init")
+	return &testRepo{dir: dir}
+}
+
+func (r *testRepo) commit(t *testing.T, name, email string) {
+	r.counter++
+	file := filepath.Join(r.dir, "file.txt")
+	os.WriteFile(file, []byte{byte(r.counter)}, 0644)
+	runGit(t, r.dir, nil, "add", ".")
+	runGit(
+		t,
+		r.dir,
+		[]string{
+			"GIT_AUTHOR_NAME=" + name,
+			"GIT_AUTHOR_EMAIL=" + email,
+			"GIT_COMMITTER_NAME=" + name,
+			"GIT_COMMITTER_EMAIL=" + email,
+		},
+		"commit",
+		"-m",
+		"commit",
+	)
+}
+
+func (r *testRepo) writeMailmap(t *testing.T, content string) {
+	if err := os.WriteFile(filepath.Join(r.dir, ".mailmap"), []byte(content), 0644); err != nil {
+		t.Fatal(err)
+	}
+}
+
+func runGit(t *testing.T, dir string, env []string, args ...string) {
+	cmd := exec.Command("git", args...)
+	cmd.Dir = dir
+	defaultEnv := []string{
+		"GIT_AUTHOR_NAME=Test",
+		"[email protected]",
+		"GIT_COMMITTER_NAME=Test",
+		"[email protected]",
+	}
+	cmd.Env = append(os.Environ(), append(defaultEnv, env...)...)
+	if out, err := cmd.CombinedOutput(); err != nil {
+		t.Fatalf("git %v: %v\n%s", args, err, out)
+	}
+}
+
+func countCommitsForEmail(contributors []contributor, email string) int {
+	for _, c := range contributors {
+		if c.Author.Email == email {
+			return c.Count
+		}
+	}
+	return 0
+}